1. Field of the Invention
The field of this invention relates generally to heat exchangers and more particularly to a heat exchanger in conjunction with a pump which is mounted within a recirculating water system where the heat of the motor is utilized to raise the temperature of the recirculating water.
2. Description of the Prior Art
The structure of the present invention is to be described in conjunction with a spa, hot tub or therapy tub which utilizes jet nozzles to circulate water within the tub where the tub may be occupied by one or more humans. However, the present invention could be used with liquids other than water. Such tubs have a circulating water system which utilizes a pump which has a motor with the motor causing rotation of a centrifugal impeller which functions to cause the water to move through the circulating system. It is desirable to heat the water within these tubs with generally this water being between one hundred degrees fahrenheit and one hundred and four degrees fahrenheit. A heater is generally included in conjunction with the tub with the heater functioning to raise the temperature of the recirculating water to the desired temperature level.
During the time that the tub is being used, the heat from the water is quickly lost to the ambient atmosphere. Therefore, this heat needs to be replaced. In the past, it has been common to activate the heater that is mounted in conjunction with the tub to reheat the water. However, it has been discovered that the electric motor of the pump for the recirculating water quickly becomes quite hot. It is desirable to have the motor temperature as low as possible to maintain an efficient operation, therefore it is beneficial to remove as much heat from the motor as possible.
It has been known to take some of the water that is being circulated through the system and pass that through the motor with the idea the water is used to extract the heat produced by the motor with this heat then being added back to the recirculating water. The advantage of such a heat exchange arrangement is that it increases the efficiency and longevity of operation of the motor of the pump and the heat that is normally wasted is being utilized therefore either eliminating or decreasing the requirement for an additional heater for heat to be added to the circulating water.